Conveyor belt protection device

ABSTRACT

A belt conveyor has a table on which are pivotally mounted one or more idler roll assemblies in the loading zone. These assemblies have limited tilting movement away from the direction of belt approach with the tilting movement being resisted by springs. Under normal conditions there is no tilting movement, but under abnormal loads the assemblies tilt and stop the conveyor.

United States Patent Frank J. Hitchcock;

William L. Jones, both of Lander, Wyo. 26,486

Apr. 8, 1970 Sept. 28, 1971 United States Steel Corporation lnventorsAppl. No. Filed Patented Assignee CONVEYOR BELT PROTECTION DEVICE 8Claims, 6 Drawing Figs.

11.5. C1 198/232, 198/37 Int. Cl B65 43/02 Field 0! Search 198/37, I84,232, I92

[56] Relerenc'es Cited FOREIGN PATENTS 1,228,561 11/1966 Germany 198/232Primary Examiner- Edward A. Sroka Attorney-Martin J. Carroll ABSTRACT: Abelt conveyor has a table on which are pivotally mounted one or moreidler roll assemblies in the loading zone. These assemblies have limitedtilting movement away from the direction of belt approach with thetilting movement being resisted by springs. Under normal conditionsthere is no tilting movement, but under abnormal loads the assembliestilt and stop the conveyor.

PATENTED 8EP28 IQYl SHEET 2 [1F 3 INVENTORS FRANK J. H/TCHCOCK a WILL/AM1.. JONES A rromey CONVEYOR BELT PROTECTION DEVICE This inventionrelates to a conveyor belt protection device and more particularly to adevice located in the conveyor loading zone. Conveyor belting, which isgenerally made of rubber, is subject to damage from various causes. Thisis especially true when handling coal, ore or other materials which maycontain tools, bars large rocks, pieces of steelplate or the like. Theseitems can puncture the belt and/or become lodged or caught on parts ofthe conveyor, thus resulting in long tears of the belt or other damage.Extreme overloads or large pieces of material also cause temporarybulges in the belt which may become caught on a conveyor part and resultin holes in the belt. This danger is most likely to occur at the loadingzone and, unless the danger is quickly seen and recognized and theconveyor stopped the damages to the belt mentioned above will result.

It is therefore an object of our invention to provide a safety devicefor a belt conveyor which will automatically stop the conveyor whenthere is an excessive overload.

Another object is to provide such a device that can be readily installedon existing belt conveyors.

These and other objects will be more apparent after referring to thefollowing specification and attached drawings, in which:

FIG. 1 is a side elevation of a portion of a conveyor incorporating ourinvention;

FIG. 2 is a view taken on the line lI-II of FIG. 1;

FIG. 3 is an enlarged view of a portion of FIG. 1;

FIG. 4 is an end view of FIG. 3;

FIG. 5 is a view taken on the line V-V of FIG. 1; and

FIG. 6 is a schematic view of the conveyor and the electrical controlcircuit for the operation thereof.

Referring more particularly to the drawings, reference nu-' meral 2indicates an endless belt conveyor having a loading chute 4 associatedtherewith. While shown as a horizontal troughed conveyor our inventionmay be used also with a flat conveyor or one arranged on a slope. Theconveyor 2 includes spaced-apart channels 6 having a baseplate 8supported on their upper flanges, thus forming a conveyor table 10.Mounted on the conveyor table 10 beneath the chute 4 are a plurality ofidler roll assemblies 12. While four assemblies 12 are shown in FIG. 1the number may vary. Even one such assembly is sufficient, but more thanone is preferred. Each assembly 12 consists of vertical end supports 14between which are supported rolls l6, l8 and 20. The parts so fardescribed are conventional According to our invention we provide a hinge22 at each end of each assembly 12. Each hinge 22 includes a horizontalplate 24 resting on plate 8 and supporting the end support 14. The endof the plate 24 extending beyond the end support 14 on the side awayfrom the direction of approach of belt 26 has a central pipe 28 weldedthereto with its axis substantially parallel to the axis of roll 18. Avertical plate 30 has two spaced-apart aligned pipes 32 welded thereto.The plate 30 is bolted or otherwise fastened to the exit side of endsupport 14 with the pipes 32 aligned with pipe 28. A pin 34 passingtrough the pipes 28 and 32 complete the hinge. The end of plate 24 onthe exit side of support 14 is bolted or otherwise secured to the top oftable 10. The end of plate 24 on the approach side of support 14 has twoslots 36 therethrough elongated in the direction of belt travel. A plate38 is welded to the approach side of support 14 and rests on plate 24.The table 10 and plate 38 have slots 40 and 44 therein aligned withslots 36. A bolt 46 passes through each set of aligned slots 36, 40 and44 with a spring 48 surrounding each bolt. The top end of spring 48bears against a beveled washer 50 and its bottom end bears against awasher 52 held in position by nuts 54.

A fixed idler assembly 56 is mounted on the approach side of assemblies12. The construction of assembly 56 is the same as that of assemblies 12except that it is secured directly to table 10 instead of being hingedthereto. A switch support 58 is located between idler assembly 56 andthe first hinged idler assembly 12 and is secured to table 10 by meansof a hinge 60 having its pivot axis parallel to those of hinges 22. Thesupport passes through hole 72 and has a nut 78 threaded thereon.

Each guide 74 has' a hole 80 therethrough for receiving rope 68. A ropeclamp 82 is attached to the rope 68 adjacent each guide 74 on the exitside thereof. A mercury switch 84 is mounted on support 58.

As shown in FIG. 6 the switch 84 has a contact 84c which is closed whenthe switch support 58 is in its normal upright position. The conveyor 2includes a drive roll 86 at one end which is driven from motor 88through gearbox 90 and belt 92. The motor 88 receives power fromthree-phase powerlines L1, L2, L3 through switch 94. Control power L4,L5 may be obtained from powerlines L2, L3 through transformer 96. Arelay coil 98 having normally open contact 980 and normally closedcontact 9801 is connected to powerlines L4, L5 in series with contacts840 and 980. A rest switch 100 is connected in parallel-with-contact98c. Contact 9801 is connected to powerlines L4, L5 in-series with relaycoil 102 having a normally closed contact 102a. Contact 1020 isconnected to powerlines L4, L5 in series with stop switch 104, startswitch 106, and relay coil 108 having normally open contacts 1080 inpowerlines L1, L2, and L3 and normally open contact 1080! connected inparallel with switch l06.'Usual protective devices (not shown) will beincluded in the circuits as desired.

In operation, the end supports 14 and switch support 58 are in uprightposition so that contact 84c is closed. Switch 94 is closed to supplypower to control powerlines L4 and L5. Reset switch 100 is closedmomentarily which will energize relay coil 98-thus closing its contact980 to lock the coil 98 in. This also opens contact 9801 to deenergizerelay coil 102 thus closing its contact 1020. Switch 106 is momentarilyclosed to energize relay coil 108 thus closing its contact 18c and1081.1. Closing of contacts l08c causes motor 88 to drive the conveyor 2and closing of contact 10801 locks coil 108 in. lfany of the endsupports 14 tilt about its hinge 22, it will tilt switch support 58 bymovement of wire rope 68. This will cause contact 84c to open thusdeenergizing relay coil 98 and closing contact 90!. Closing of contact9801 will energize relay coil 102 thus opening its contact 1020 which inturn will deenergize relay coil 108 to open its contacts 108:: and 108d.Opening of contacts 1080 stops the motor 88 and the conveyor 2. Theoperator then removes any material which caught on the conveyor andcaused the tilting of the end supports 14. The end supports 14 andswitch support 58 are then restored to their upright position and thecircuits reset as described above to restart the conveyor.

While one embodiment of our invention has been shown and described, itwill be apparent that other adaptations and modifications may be madewithout departing from the scope of the following claims.

We claim:

1. In a conveyor having a conveyor support, a plurality of idler rollassemblies supported on said support, each assembly including at leastone roll and end supports for said roll, a belt mounted on said rollsfor movement thereover, fixedly loading area for supplying a load tosaid conveyor, and means for furedly supporting the roll assembly on theentry side of said loading area; the improvement comprising pivot meansfor supporting each of a plurality of said roll assemblies in saidloading area for movement of the top of said assemblies away from thedirection of belt approach, each of said pivot means including a hingeconnected to each end support of the roll assembly on the exit sidethereof adjacent its lower end; a switch support pivotally supported onsaid table between the fixed roll assembly at the entry end of saidloading area and the adjacent pivoted roll assembly, said switch supporthaving a switch mounted thereon; and switch actuating means including aguide secured to each of said pivoted roll assemblies, each of saidguides having a hole therethrough in alignment with the holes in theother guides, a tension member passing through the aligned holes in saidguides, means fastening one end of said tension member to said switchsupport, and means secured to said tension member adjacent each of saidguides on the exit side thereof whereby pivoted movement of any of saidpivotally supported idler roll assemblies will move said switch supportand actuate said switch.

2. The combination of claim 1 in which said conveyor support is a table,and said pivot means includes an upwardly extending plate secured tosaid end support on the exit side thereof adjacent its lower end, asecond plate resting on said table beneath said end support andextending from both sides thereof, and means pivotally connecting saidplates, means fastening the exit end of said second plate to said table,said second plate having a hole therethrough on the belt approach side,a third plate secured to the approach side of said end support adaptedto contact the top of said second plate, said third plate and tablehaving holes therein aligned with the hole in said second plate, a boltextending through said aligned holes downwardly below the top of saidtable, and a spring surrounding said bolt with its top end supportedbeneath the top of said table and its bottom end supported adjacent thebottom and of said bolt.

3. The combination of claim 2 including a spring having one end securedto said switch support and the other end secured to said fixed rollassembly.

4. The combination of claim 3 in which said tension member is a wirerope, and the means secured thereto is a rope clamp.

5. The combination of claim 4 in which said switch is a mercury switchadapted to be closed in one position of said support and open in anotherposition thereof.

6. The combination of claim 1 including a spring having one end securedto said switch support and the other end secured to said fixed rollassembly.

7. The combination of claim 6 in which said tension member is a wirerope, and the means secured thereto is a rope clamp.

8. The combination of claim 7 in which said switch is a mercury switchadapted to be closed in one position of said support and open in anotherposition thereof.

1. In a conveyor having a conveyor support, a plurality of idler rollassemblies supported on said support, each assembly including at leastone roll and end supports for said roll, a belt mounted on said rollsfor movement thereover, a loading area for supplying a load to saidconveyor, and means for fixedly supporting the roll assembly on theentry side of said loading area: the improvement comprising pivot meansfor supporting each of a plurality of said roll assemblies in saidloading area for movement of the top of said assemblies away from thedirection of belt approach, each of said pivot means including a hingeconnected to each end support of the roll assembly on the exit sidethereof adjacent its lower end; a switch support pivotally supported onsaid table between the fixed roll assembly at the entry end of saidloading area and the adjacent pivoted roll assembly, said switch supporthaving a switch mounted thereon; and switch actuating means including aguide secured to each of said pivoted roll assemblies, each of saidguides having a hole therethrough in alignment with the holes in theother guides, a tension member passing through the aligned holes in saidguides, means fastening one end of said tension member to said switchsupport, and means secured to said tension member adjacent each of saidguides on the exit side thereof whereby pivoted movement of any of saidpivotally supported idler roll assemblies will move said switch supportand actuate said switch.
 2. The combination of claim 1 in which saidconveyor support is a table, and said pivot means includes an upwardlyextending plate secured to said end support on the exit side thereofadjacent its lower end, a second plate resting on said table beneathsaid end support and extending from both sides thereof, and meanspivotally connecting said plates, means fastening the exit end of saidsecond plate to said table, said second plate having a hole therethroughon the belt approach side, a third plate secured to the approach side ofsaid end support adapted to contact the top of said second plate, saidthird plate and table having holes therein aligned with the hole in saidsecond plate, a bolt extending through said aligned holes downwardlybelow the top of said table, and a spring surrounding said bolt with itstop end supported beneath the top of said table and its bottom endsupported adjacent the bottom end of said bolt.
 3. The combination ofclaim 2 including a spring having one end secured to said switch supportand the other end secured to said fixed roll assembly.
 4. Thecombination of claim 3 in which said tension member is a wire rope, andthe means secured thereto is a rope clamp.
 5. The combination of claim 4in which said switch is a mercury switch adapted to be closed in oneposition of said support and open in another position thereof.
 6. Thecombination of claim 1 including a spring having one end secured to saidswitch support and the other end secured to said fixed roll assembly. 7.The combination of claim 6 in which said tension member is a wire rope,and the means secured thereto is a rope clamp.
 8. The combination ofclaim 7 in which said switch is a mercury switch adapted to be closed inone position of said support and open in another position thereof.